First and foremost there is more to Ruby then Rails. Rails is one framework albeit the most popular Ruby framework. Ruby as a community is growing and developers are writing cool things with it. It's also available on the JVM and there is Ruby implementation written mostly in Ruby.

I think the problem here is that the author is writing about "Rails Developers". <language/framework> developers usually have a narrow minded view about other languages/frameworks and hence call themselves <language/framework> developers. Real developers use the right tool for the job.

I've come across some really delightful developers who write Ruby/Rails who are pretty appreciative of other languages. This notion that all developers who use Rails are arrogant is not true anymore IMHO.